Cardiovascular surgery has traditionally been performed with open surgical techniques. These techniques typically involve invasive procedures to surgically excise diseased tissue before sewing in an artificial replacement, which may often require prolonged clamping to halt blood flow through the diseased segment. These open surgical techniques can only be performed on relatively healthy patients and often result in relatively long recovery periods. Recently, minimally invasive techniques have been developed and used with endovascular or catheter-directed methodologies. However, minimally invasive techniques can create a new set of complications that need to be dealt with, such as embolus formation.
In several diseased states, the cardiovascular system may develop thrombus buildup. One area where thrombus buildup is troublesome is the aortic arch. If blood flow from the heart is not hemodynamically normal, it can result in thrombus deposition throughout the arch. This can be a result of aortic valve stenosis creating regurgitation and subsequent turbulent flow in the aortic arch. Alternatively, it could be caused by aneurysmal dilation which causes slower than normal velocities as well as regions along the curvature of the bulge where recirculating zones and stagnation develop, which lead to further thrombus formation.
In order to repair the large cardiovascular structures near the heart, relatively large catheter systems often need to be advanced across the aortic arch. These larger catheter systems are relatively stiff, so they may require additional force to advance around the curvature of the arch. The relative stiffness of the catheter may bias the catheter toward the outer curvature of the arch, and the resulting forces generated can break emboli free when the catheter is advanced through thrombotic regions.
Once broken free, there are three main sets of outlets through which such emboli may travel: the great vessels, the visceral branch vessels, or the distal/lower extremities. Emboli travelling to the distal extremities can be marginally problematic. Emboli travelling through the great vessels to the arms can also be marginally problematic. But emboli travelling through the great vessels to the brain could result in a stroke. Further, emboli travelling to the branch vessels of the visceral segment could be very problematic as well, because emboli can cause bowel ischemia which can be deadly. As the size and number of emboli increase, they become more problematic.